Abstract
OBJECTIVE: The objective of this three-wave longitudinal study was to investigate the temporal precedence between the motivational drivers in self-determination theory (SDT) and the social cognitive factors in theory of planned behaviour (TPB). METHOD: A total of 236 patients who underwent anterior cruciate ligament (ACL) reconstruction surgery (M(age) = 33.58 ± 10.03, range = 18 to 59; female = 46.2%) completed surveys assessing autonomous motivation from SDT, and attitude, subjective norms, perceived behavioural control (PBC), and intention from TPB, and rehabilitation adherence, at baseline (T1), and at 2 months (T2) and 4 months (T3) post-baseline. RESULTS: In a three-wave cross-lagged panel model, autonomous motivation prospectively related to subsequent attitude, subjective norms and PBC, whereas reverse paths were generally small; attitude showed a modest reciprocal link with autonomous motivation. Additionally, a mediation model revealed that T1 autonomous motivation had significant indirect effects on T3 rehabilitation adherence via T2 social cognitive factors and intention, whereas only T1 subjective norms had small indirect effects on T3 rehabilitation adherence through T2 autonomous motivation and intention. CONCLUSIONS: These findings support the notion that autonomous motivation precedes social cognitive factors, as proposed in the integrated theoretical model of SDT and TPB. Future research, including experimental interventions, can use the integrated theoretical model to promote various health behaviours, such as rehabilitation protocols, healthy eating habits and hygiene practices.